<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta http-equiv="X-UA-Compatible" content="IE=edge">
	<title>css性能优化</title>
	<link rel="stylesheet" href="test.css">
	<style>
		.paragraph{
			font-size: 18px;
		}
	</style>
</head>
<body>
	<p class="paragraph" style="font-size: 20px;position: relative;">这是一个测试段落</p>
</body>
</html>

.paragraph{
	font-size:15px;
}